#11569(documentation:new): A correction to the docs
If used together with -vcodec copy, it will affect the aspect ratio stored at container level, but not the aspect ratio stored in encoded
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Type: defect Status: new | Priority: normal Component: | Version: documentation | unspecified Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- In the documentation to the ffmpeg tool, at the end of the -aspect option description there's a phrase: frames, if it exists. Here "stored at ''container'' level" should probably be replaced with "stored at ''video stream metadata'' level". ffmpeg N-118724-g73f4668ef8-20250310. -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by Gyan): The change makes it less accurate and less precise. Do you think otherwise? Why? -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:1> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
Do you think otherwise? Why? I do, the reason is this: if you change aspect ratio with a command like
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by idest): this: {{{ ffmpeg -i in.mp4 -aspect 11:3 -vcodec copy out.mp4 }}} , and then analyze the resulting video with ffprobe: {{{ ffprobe -show_format -show_streams out.mp4 }}} , you'll notice that the "sample_aspect_ratio" and "display_aspect_ratio" values, which are related to aspect ratio, are shown in the [STREAM] (video stream metadata) section, not in the [FORMAT] (container level) one. -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:2> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by Cigaes): Your assumption that `[FORMAT]` = “container level” is unfounded. `[STREAM]` contains information both from the container and the bitstream. -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:3> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by idest):
Your assumption that [FORMAT] = “container level” is unfounded. I think it's what ffprobe documentation says:
1. (in the "Description" section): Metadata tags stored in the container or in the streams are recognized and printed in the corresponding "FORMAT", "STREAM", "STREAM_GROUP_STREAM" or "PROGRAM_STREAM" section. 2. (in the -show_format description): All the container format information is printed within a section with name "FORMAT". 3. (in the -show_streams description): Each media stream information is printed within a dedicated section with name "STREAM". -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:4> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by Cigaes): Looks accurate. Note that the aspect ratio is not part of what is specifically called metadata. -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:5> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by Gyan): Container information is that which is written by the muxer. Video stream metadata i.e. metadata stored about a stream can be 1) written into a container field by the muxer and/or 2) embedded within the coded bitstream by the encoder or a bitstream filter. `-aspect` only affects (1). -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:6> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by idest):
-`aspect` only affects (1). Sorry if I'm being stupid now, but doesn't the phrase
"If used together with -vcodec copy, it will affect the aspect ratio stored at container level, but not the aspect ratio stored in encoded frames, if it exists" (that's from -aspect description) imply that `-aspect` affects (2) if used without `-vcodec copy`? -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:7> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: A correction to the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Comment (by Gyan): If encoding, -aspect affects both (1) and (2). -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:8> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
#11569: Question on "-aspect" in the docs -------------------------------------+------------------------------------- Reporter: idest | Owner: (none) Type: defect | Status: new Priority: normal | Component: | documentation Version: unspecified | Resolution: Keywords: | Blocked By: Blocking: | Reproduced by developer: 0 Analyzed by developer: 0 | -------------------------------------+------------------------------------- Changes (by MasterQuestionable): * cc: MasterQuestionable (added) * summary: A correction to the docs => Question on "-aspect" in the docs Comment: ͏ https://ffmpeg.org/ffmpeg.html#Video-Options -- Ticket URL: <https://trac.ffmpeg.org/ticket/11569#comment:9> FFmpeg <https://ffmpeg.org> FFmpeg issue tracker
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